How to enter BIOS or CMOS setup

Due to the diversity of computer manufacturers and BIOS in the evolution of a computer, there are many ways to enter the BIOS or CMOS Setup. Below is a list of most of these methods, as well as other suggestions for importing BIOS settings.

Note: Apple, or Mac, the computer does not have a BIOS and instead uses an EFI, which does not need to be modified based on the hardware in the computer, such as a BIOS. EFI provides better integration between hardware and software for Apple computers, virtually eliminating the need for a BIOS.

Note: This documentation does not help if you are unable to enter CMOS settings with the password.

New computer version

Computers manufactured in the past few years allow you to enter BIOS settings using one of the five keys shown below during the boot process.

  • F1
  • F2 *
  • F10 **
  • DEL
  • ESC

Note: F1, F2 and F10 are all function keys on the top of the keyboard.

* If pressing F2 will open the diagnostic tool, your setting key is likely F10

** F10 is also used for boot menu. If F10 opens boot menu, your setup key is likely F2.

The setup keys will be pressed when the computer boots up. Most users will see a message similar to the example below upon boot. Some older computers may also display a flashing block to indicate when F1 or F2 is pressed.

Press to enter BIOS setup

Tip: If your computer is new and you are not sure which key to press when it boots, try pressing and holding one or more keys on your keyboard to cause a stuck key error. When you get this error you should have the option to go ahead or enter setup.

Note: If you are still unable to enter BIOS using the methods listed above, check your motherboard for the proper key to enter BIOS. Motherboard documentation can also be found on the manufacturer’s website.

Once you have successfully entered the CMOS setup, you should see a screen similar to the example below. Your CMOS setup may look slightly different, depending on the manufacturer, but there are still most of the same options in the menu on the left or along the bottom of the screen.

How can I change and save changes in CMOS settings?

Once CMOS is set up, the method to change the setting usually depends on the BIOS manufacturer. You can use the arrow keys together with the Enter key to select categories and change their values. Some manufacturers may require you to press the Page up and Page down keys to change the value.

Tip: All manufacturers show the navigation keys at the bottom or right side of the screen.

The values cannot be changed to the setting you want to use

If you are trying to change the clock, speed, or other settings and there is no option available, it is because it is not supported by the motherboard. If you believe it needs support, you may need a BIOS update.

Tip: If changes you make appear to revert to the default settings or the date and time set in the BIOS do not stop falling behind, you may need to replace the CMOS battery.

How do I save changes?

If any changes are made, you need to save those changes, which are usually done by pressing the F10 key on the keyboard. If F10 doesn’t work, look at the bottom or top of the screen for the key used to save the settings.

Old version computer

Unlike today’s computers, older computers (before 1995) already have a lot of methods to install BIOS. Below is a list of the main sequences for press when the computer is booting to enter BIOS setup.

  • CTRL + ALT + ESC
  • CTRL + ALT + INS
  • CTRL + ALT + ENTER
  • CTRL + ALT + S
  • PAGE UP KEY
  • PAGE DOWN KEY

ACER BIOS

If your computer is unable to boot or you want to restore the BIOS to boot setup and your computer uses an ACER BIOS, press and hold the F10 key as you turn on the computer. While continuing to hold down the F10 key, you will hear two beeps indicating that the settings are restored.

AMI BIOS

Older AMI BIOS can be reverted back to boot settings by pressing and holding the Insert key when the computer is booted.

BIOS or CMOS floppy disk

At the beginning of 486, 386, and 286 computers needed a floppy disk to enter BIOS setup. The floppy disks may be called ICU, BBU, or SCU disks. Because the floppy disks are unique to your computer manufacturer, you must obtain the floppy disk from them. See list of computer manufacturers for contact information.

Early IBM computer

Some Early IBM computers require you to press and hold both mouse buttons as the computer boots to enter BIOS setup.